The present application claims priority under 35 USC 119 to Japanese Patent Application No. 2000-396770 filed on Dec. 27, 2000 the entire contents thereof is hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a shock absorbing construction for motorcycles in which a shock absorbing member projecting from the vehicle body is provided so that the shock absorbing member absorbs the impact by collapsing.
2. Description of Background Art
FIG. 7 is a side view of a shock absorbing construction for a motorcycle according to related art. A shock absorbing member 105 is mounted above a front wheel 104 which is mounted on a fork 103 on the head pipe 102 provided on a vehicle body frame 101 of a motorcycle 100. A deforming element (hereinafter referred to as xe2x80x9cshock absorbing memberxe2x80x9d) 105 is mounted at the front end of the vehicle body frame 101.
The shock absorbing member 105 is manufactured by filling foam material 108 in a hollow portion of a frame body 106.
FIGS. 8(a) and 8(b) are explanatory drawings showing the operation of the shock absorbing construction for motorcycles of the related art.
In FIG. 8(a), when a motorcycle 100 (shown in FIG. 7) comes into collision with an obstruction, the tip portion 105a of the shock absorbing member 105 hits the obstruction, and an impact force F1 generated by collision acts on the tip portion 105a as shown by the arrow.
In FIG. 8(b), when an impact force F1 acts on the tip portion 108a of the foam material 108, the tip portion 108a is collapsed. Accordingly, by collapsing the tip portion 105a of the shock absorbing material 105 as much as the amount of collapse L1, an impact force F1 is absorbed to protect the occupant.
Incidentally, when the tip potion 108a of the foam material 108 is collapsed, the space in the foam material 108 is decreased, and thus it resists being collapsed. Therefore, when the foaming space is too small, it is difficult to ensure a sufficient amount of collapse of the shock absorbing member 105, and thus an impact force cannot be absorbed sufficiently.
In order to absorb an impact force sufficiently, it is conceivable to increase the foaming space in the foam material 108 so that the amount of collapse of the foam material 108 is also increased.
However, when the forming space in the foam material 108 is too much, the foam material 108 can be collapsed easily. Therefore, in order to absorb an impact force by means of the foam material 108 with a large amount of foaming space, it is required to increase the size of the foam material 108 to ensure the increased amount of collapse of the foam material 108. As a consequent, the dimensional standard of the shock absorbing member increases too much and thus it is difficult to put it into practical use.
Accordingly, it is an object of the present invention to provide a shock absorbing construction for motorcycles that has a dimensional standard suitable for practical use that can absorb the impact force sufficiently.
In order to achieve the object described above, the present invention provides a shock absorbing construction for motorcycles including a shock absorbing member projecting from the vehicle body that allows the shock absorbing member to absorb an impact force by collapsing. The shock absorbing member includes a plurality of cavities and a reinforcing rib for dividing the adjacent cavities. All or some of the reinforcing ribs are formed with a thinner portion.
By forming a thinner portion on all or some of the reinforcing ribs, the strength of the reinforcing ribs can be controlled. Therefore, the strength of the shock absorbing member can be adequately adjusted for the impact force.
In addition, providing a plurality of cavities helps to accommodate the reinforcing ribs in these cavities when the shock absorbing member is collapsed. Therefore, a sufficient amount of collapse of the shock absorbing member is ensured.